Problem: Subtract.
Solution: There are many ways to solve this problem. Let's see two ways we can solve it. Place Value We can think in terms of tenths: $\begin{aligned} &\phantom{=}48.2 -5.8\\\\ &=482\text{ tenths} - 58\text{ tenths}\\\\ &=424\text{ tenths}\\\\ &=42.4 \end{aligned}$ Place value table Let's line up the numbers by their decimal places. Tens Ones $.$ Tenths $4$ ${8}$ $.$ ${2}$ $5$ $.$ ${8}$ Now, let's subtract each place value column. Tens Ones $.$ Tenths ${4}$ $\overset{7}{\cancel{{8}}}$ $.$ $\overset{12}{\cancel{{2}}}$ $-$ ${5}$ $.$ ${8}$ $\underline{~~~~}$ $\underline{~~~~}$ $\underline{~~~~}$ $\underline{~~~~}$ $4$ $2$ $.$ $4$ $42.4=48.2 - 5.8$